Methods and systems for a network appliance module enabling dynamic VDC aware span

ABSTRACT

Embodiments of the present disclosure enable monitoring network traffic on multiple Virtual Device Context (VDC) elements of a switch using a single NAM module. To that end, if a monitored network element supports contexts (i.e. VDC elements), a NAM module could be configured to seamlessly drive the move of the data port interfaces (at the managed device) from one context to the other. After the move of the data ports that support SPAN destination traffic flow to the target VDC is complete, these SPAN destination ports may be configured to be able to receive SPAN data traffic.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority under 35 U.S.C. § 119(e)to U.S. Provisional Application Ser. No. 62/106,057, entitled “METHODSAND SYSTEMS FOR A MONITORING DEVICE TO EXECUTE COMMANDS ON AN ATTACHEDSWITCH” filed Jan. 21, 2015, and U.S. Provisional Application Ser. No.62/106,064, entitled “METHODS AND SYSTEMS FOR A NETWORK APPLIANCE MODULEENABLING DYNAMIC VDC AWARE SPAN,” filed Jan. 21, 2015, which are herebyincorporated by reference in their entirety.

TECHNICAL FIELD

This disclosure relates in general to the field of communications and,more particularly, to a method and an apparatus for enabling networkappliance monitoring.

BACKGROUND

Data centers are increasingly used by enterprises for effectivecollaboration, data storage, and resource management. A typical datacenter network contains myriad network elements including servers, loadbalancers, routers, switches, etc. The network connecting the networkelements provides secure user access to data center services and aninfrastructure for deployment, interconnection, and aggregation ofshared resources. Improving operational efficiency and optimizingutilization of resources in data centers are some of the challengesfacing data center managers. Data center managers seek a resilientinfrastructure that consistently supports diverse applications andservices. A properly planned data center network provides applicationand data integrity and, further, optimizes application availability andperformance.

BRIEF DESCRIPTION OF THE DRAWINGS

To provide a more complete understanding of the present disclosure andfeatures and advantages thereof, reference is made to the followingdescription, taken in conjunction with the accompanying figures, whereinlike reference numerals represent like parts, in which:

FIG. 1A is a simplified schematic diagram illustrating a physical viewof a system for providing service appliances in a network environment inaccordance with some embodiments of the present disclosure;

FIG. 1B is a simplified schematic diagram illustrating a logical view ofthe system in accordance with some embodiments of the presentdisclosure;

FIG. 2 is a simplified block diagram illustrating details of the systemin accordance with some embodiments of the present disclosure;

FIG. 3 illustrates a Network Appliance Monitoring mechanism for mininginformation by remotely executing commands in accordance with someembodiments of the present disclosure;

FIG. 4 illustrates a single NAM module configured to monitor traffic onmultiple VDCs in accordance with some embodiments of the presentdisclosure;

FIG. 5 illustrates VDC aware SPAN extended to multiple chassis inaccordance with some embodiments of the present disclosure; and

FIG. 6 illustrates a NAM module communicatively connected to two N7k forVPC in accordance with some embodiments of the present disclosure.

OVERVIEW

In one aspect of the present disclosure, a method for enabling networkappliance monitoring is disclosed. In particular, a method for amonitoring device such as a network appliance monitoring (NAM) module toexecute one or more commands on a network element (e.g. a switch) towhich the NAM module is connected to is disclosed. The method includesproviding the command from the NAM module to the network element over afirst communication channel between the NAM module and the networkelement, the command triggering the network element to determine whetherexecution of the command on the network element is allowed and, uponpositive determination, execute the command on the network element. Themethod also includes receiving, at the NAM module, from the networkelement, at least part of an output resulting from the execution of thecommand.

Another aspect of the present disclosure takes place in a setting wherea NAM module includes a NAM data port physically connected, over a datacommunication link, to a data port of a network element (e.g. a switch)that is allocated to a first Virtual Design Context (VDC) element of aplurality of VDC elements instantiated on (i.e., active in) the networkelement so that the NAM module can monitor traffic flow on the first VDCelement. In this aspect of the present disclosure, a method for the NAMmodule to monitor traffic flow from a second VDC element (i.e. a VDCelement different from the first VDC element) is disclosed. The methodincludes providing, from the NAM module, to the network element, over amanagement communication link between the NAM module and the networkelement (i.e. over the bi-directional connection for exchanging controltraffic), a first command triggering the network element to allocate thenetwork element data port to the second VDC element (i.e. to trigger thenetwork element to logically move data port interfaces so that the NAMcan receive traffic flow from the second VDC element), and followingallocation of the network element data port to the second VDC element,monitoring traffic on the second VDC element by receiving, at the NAMmodule, from the network element, over the data communication linkbetween the NAM data port and the network element data port (i.e., overthe uni-directional data link between the data port of the NAM moduleand the data port of the switch that is now allocated to the secondVDC), the traffic flow from the second VDC element.

In an aspect, a method for a NAM module to monitor network traffic onmultiple VDCs of one or more network elements (managed devices) isdisclosed. The method includes seamlessly driving a move of data portinterfaces from an original VDC to a target VDC, and enablingconfiguration of the data ports to receive SPAN data traffic. In anembodiment, the data ports may comprise data ports supporting SPANdestination traffic flow to the target VDC. In an embodiment, the stepof seamlessly driving the move may include the NAM module providing oneor more parameters, such as e.g. a data port, the target VDC, and SPANresource port, to the one or more network elements. In an embodiment,the NAM module may be configured to communicate with the one or morenetwork elements via one or more RISE channels. In an embodiment, theNAM module may further be configured to perform network appliancemonitoring on the target VDC.

For all aspects of the present disclosure, a graphical user interface(GUI) may be provided that enable a user/administrator of a NAM moduleto control the various functionality described herein, such as remoteexecution of commands on a network element or reconfiguration of dataport interfaces to monitor traffic in a target VDC. For example, such aGUI could be configured to enable a user/administrator to at leastprovide user input indicating the target VDC as well as, optionally,provide user input indicating a data port and SPAN resource port. A GUIcould be displayed on a display of an electronic device, e.g. on adisplay of the NAM module or a controller associated with the NAMmodule.

As will be appreciated by one skilled in the art, aspects of the presentdisclosure, in particular the functionality of the NAM module describedherein as well as the functionality of the network element (includingany of the VDCs instantiated on that element) that the NAM module isconfigured to monitor, may be embodied as a system, a method or acomputer program product. Accordingly, aspects of the present disclosuremay take the form of an entirely hardware embodiment, an entirelysoftware embodiment (including firmware, resident software, micro-code,etc.) or an embodiment combining software and hardware aspects that mayall generally be referred to herein as a “circuit,” “module” or“system.” Functions described in this disclosure may be implemented asan algorithm executed by a processor, e.g. a microprocessor, of acomputer. Furthermore, aspects of the present disclosure may take theform of a computer program product embodied in one or more computerreadable medium(s), preferably non-transitory, having computer readableprogram code embodied, e.g., stored, thereon. In various embodiments,such a computer program may, for example, be downloaded (updated) to theexisting devices and systems (e.g. to the existing service appliances aswell as to the existing network elements such as the existing routers,switches, various control nodes, etc.) or be stored upon manufacturingof these devices and systems.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

System Overview: Service Appliances and Network Switches

FIGS. 1A-B and 2 show examples of a system architecture for providingservice appliances in a network environment, and specifically, providingservice appliances as virtual line cards in a network switch. Thevirtual line card allows the service appliances to be located anywherein the network, but other ways of providing the service appliance (e.g.,directly connecting the service appliance on the switch) are alsopossible. It is noted that the examples are merely illustrative and arenot intended to be limiting. Other architectures and configurations areenvisioned by the disclosure.

FIG. 1A is a simplified schematic diagram illustrating a physical viewof a system 10 for providing service appliances in a networkenvironment. FIG. 1 includes a network (illustrated as multiple links12) that connects one or more server farms 14 a and 14 b to one or moreclients 16 via a cloud 18. Cloud 18 may encompass any public,semi-public, and/or private networks including enterprise networks, anInternet or intranet, community networks, etc. Individual servers inserver farm 14 a and 14 b may communicate within the same farm viaswitches 20 a and 20 b, respectively. Servers in server farm 14 a maycommunicate with servers in server farm 14 b via a switch 22 in thisparticular example implementation.

A service appliance 24 may connect to switch 22 over a communicationchannel 26 (e.g., over a port-channel). As used herein, a “communicationchannel” encompasses a physical transmission medium (e.g., a wire), or alogical connection (e.g., a radio channel, a network connection) used toconvey information signals (e.g., data packets, control packets, etc.)from one or more senders (e.g., switch 22) to one or more receivers(e.g., service appliance 24). A communication channel, as used herein,can include one or more communication links, which may be physical(e.g., wire) or logical (e.g., data link, wireless link, etc.).Termination points of communication channels can include interfaces suchas Ethernet ports, serial ports, etc. In embodiments of system 10,communication channel 26 may be a single channel: deployed for bothcontrol messages (i.e., messages that include control packets) and datamessages (i.e., messages that include data packets).

As used herein, a “service appliance” is a discrete (and typically, butnot necessarily, separate) hardware device with integrated software(e.g., firmware), designed to provide one or more network servicesincluding load balancing, firewall, intrusion prevention, virtualprivate network (VPN), proxy, etc. In some cases, switch 22 may beconfigured with an intelligent service card manager module (ISCM) 28,and service appliance 24 may be configured with a correspondingintelligent service card client module (ISCC) 30. ISCM 28 and ISCC 30can form part of a Remote Integrated Service Engine (RISE)infrastructure for configuring service appliance 24 on the switch, e.g.,as a virtual line card in switch 22.

FIG. 1B is a simplified schematic diagram illustrating a logical view ofsystem 10. In some cases, ISCC 30 and ISCM 28 may be configured to allowservice appliance 24 to appear as a virtual line card 25, or some othervirtual network node/entity. The terms “line card” and “service module”are interchangeably used herein to refer to modular electronic circuitsinterfacing with telecommunication lines (such as copper wires oroptical fibers) and that offer a pathway to the rest of atelecommunications network. Service appliance is often referred simplyas “appliance” or “module” herein. Hence, virtual line card 25 isinterchangeable (in certain instances) with ISCM 28. A virtual servicemodule (or a virtual line card) is a logical instance (of a servicemodule) providing the same functionalities (as the service module).Service modules may perform various functions including providingnetwork services (e.g., similar to service appliances). One differencebetween a service module and a service appliance is that the servicemodule may be physically located within a switch, for example, on anappropriate slot. Virtual service modules are similarly configurablewithin a switch.

Broadly speaking, RISE (or comparable technologies) allows (external)service appliances connect to a switch and behave like a service modulewithin a switch without having to take up a physical slot in the switch.RISE helps consolidate how the appliances are provisioned, and enablesthe appliances to have the benefits of being a service module within theswitch. The task for provisioning and configuring of these serviceappliances is performed mostly by RISE being provided on the switch,making it easy for network administrators to add/remove serviceappliances in the network.

According to embodiments of the present disclosure, an appliance usercan enjoy the same benefit of a service module's simple configurationand operation using the infrastructure of system 10. For example,setting up service appliance 24 for network configurations may beunnecessary. Substantially all such configurations may be made viaswitch 22, instead of service appliance 24. Service appliance 24 mayoffload (i.e., transfer) any network (e.g., L2/L3 network) specificcontrol plane and data plane operations to switch 22. Data pathacceleration that leverages an application specific integrated circuit(ASIC) (potentially embedded in switch 22) may also be possible invarious embodiments. Switch 22 may communicate control messages toservice appliance 24 over communication channel 26. Thus, configurationand provisioning of services within service appliance 24 may beimplemented via switch 22.

Note that the numerical and letter designations assigned to the elementsof FIGS. 1A and 1B do not connote any type of hierarchy; thedesignations are arbitrary and have been used for purposes of teachingonly. Such designations should not be construed in any way to limittheir capabilities, functionalities, or applications in the potentialenvironments that may benefit from the features of system 10. For easeof description, only two representative server farms are illustrated inFIGS. 1A and 1B. Any number of server farms and switches may beconnected in the network without departing from the broad scope of thepresent disclosure.

For purposes of illustrating the techniques of system 10, it isimportant to understand the communications in a given system such as thesystem shown in FIGS. 1A and 1B. The following foundational informationmay be viewed as a basis from which the present disclosure may beproperly explained. Such information is offered earnestly for purposesof explanation only and, accordingly, should not be construed in any wayto limit the broad scope of the present disclosure and its potentialapplications.

Typically, network services such as load balancing, firewall, intrusionprevention, proxy, virtual private network (VPN), etc. are providedthrough one or more of the following options: (1) service appliancesthat connect to network switches and routers; (2) specially designedhigh-performance routers configured with the services; or (3) networkdevices such as routers or switches that are configured with servicemodules that provide the services.

Typical service appliances (e.g., load balancers) integrate servicessuch as load balancing, firewall, intrusion prevention, VPN, etc. in asingle box format, which is generally based on modular, scalableplatforms and which provides the most cost-effective option of the threeoptions listed previously. Service appliances are typically connectedexternally to a switch (e.g., aggregate switch or access switch, etc.)via appropriate ports. Different service appliances are designed withspecific features applicable to different network environments. Theservice appliances may be deployed independently to service-specificareas of the network infrastructure, or they may be combined for alayered approach. Service appliances are typically located between theclients and server farms. Data packets generally pass through theservice appliances on the way to (and from) the servers/clients. Theservice appliances may be managed by a management application (e.g.,software) on the service appliance that enables configuration settingsand other management functions.

Network services may also be provided by specially designedhigh-performance routers. Such routers may implement a massive parallelprocessor hardware and software architecture to deliver integratednetwork services (e.g., firewall, deep packet inspection, etc.). Many ofthe functionalities are embedded in a specially designed processor inthe router. For example, such a specially designed router can provide anintegrated security solution (e.g., stateful packet filtering, intrusiondetection and prevention, per-user authentication and authorization, VPNcapability, extensive QoS mechanisms, multiprotocol routing, voiceapplication support, and integrated WAN interface support) and routingin a single box.

Network services may also be integrated into a network device (such as aswitch or router) using dedicated line cards. The line cards aretypically installed inside the device, allowing any port on the deviceto operate as a firewall port, while integrating the services inside thenetwork infrastructure. Several line cards may be installed in the samechassis, providing a modular solution where needed. Such solutionspermit the user to take advantage of existing switching and routinginfrastructure without any costly upgrades.

Turning to the potential infrastructure of FIGS. 1A and 1B, the examplenetwork environment may be configured as one or more networks and,further, may be configured in any form including, but not limited to,local area networks (LANs), wireless local area networks (WLANs),virtual local area networks (VLANs), metropolitan area networks (MANs),wide area networks (WANs), VPNs, Intranet, Extranet, any otherappropriate architecture or system, or any combination thereof thatfacilitates communications in a network. In some embodiments, acommunication link may represent any electronic link supporting a LANenvironment such as, for example, cable, Ethernet, wireless technologies(e.g., IEEE 802.11x), ATM, fiber optics, etc. or any suitablecombination thereof. In other embodiments, communication links mayrepresent a remote connection through any appropriate medium (e.g.,digital subscriber lines (DSL), telephone lines, T1 lines, T3 lines,wireless, satellite, fiber optics, cable, Ethernet, etc. or anycombination thereof) and/or through any additional networks such as awide area networks (e.g., the Internet).

Elements of FIGS. 1A and 1B may be coupled to one another through one ormore interfaces employing any suitable connection (wired or wireless),which provides a viable pathway for electronic communications.Additionally, any one or more of these elements may be combined orremoved from the architecture based on particular configuration needs.System 10 may include a configuration capable of transmission controlprotocol/Internet protocol (TCP/IP) communications for the electronictransmission or reception of packets in a network. System 10 may alsooperate in conjunction with a user datagram protocol/IP (UDP/IP) or anyother suitable protocol, where appropriate and based on particularneeds. In addition, gateways, routers, switches, and any other suitablenetwork elements may be used to facilitate electronic communicationbetween various nodes in the network.

Switches in system 10, including switches 22, 20 a, and 20 b, mayinclude any type of network element connecting network segments. Forexample, switches 22, 20 a, and 20 b may include a multi-port networkbridge that processes and routes data at a data link layer (Layer 2). Inanother example, switches 22, 20 a, and 20 b may process data at anetwork layer (Layer 3), or Layer 4 (with network address translationand load distribution), or Layer 7 (load distribution based onapplication specific transactions), or at multiple layers (e.g., Layer 2and Layer 3). In certain embodiments, functionalities of switches 22, 20a, and 20 b may be integrated into other network devices such asgateways, routers, or servers. In various embodiments, switches 22, 20a, and 20 b may be managed switches (e.g., managed using a command lineinterface (CLI), a web interface, etc.).

Communication channel 26 may include a port-channel, which can encompassan aggregation of multiple physical interfaces into one logicalinterface, for example, to provide higher aggregated bandwidth, loadbalancing and link redundancy. Communication channel 26 with multiplelinks can provide a high availability channel: if one link fails,traffic previously carried on this link can be switched to the remaininglinks. Communication channel 26 may contain up to 16 physicalcommunication links and may span multiple modules for added highavailability. In one embodiment, communication channel 26 can representa port-channel with an aggregation of four point-to-point communicationlinks over multiple ports. In another embodiment, communication channel26 can represent a virtual port-channel (vPC).

Although FIGS. 1A and 1B show server farms 14 a and 14 b, it should beappreciated that system 10 is not limited to servers. In fact, anynetwork element may be connected to the network via appropriateswitches, where these implementations may be based on particular needs.As used herein, the term “network element” is meant to encompasscomputers, network appliances, servers, routers, switches, gateways,bridges, load balancers, firewalls, processors, modules, or any othersuitable device, component, proprietary element, or object operable toexchange information in a network environment. Moreover, the networkelements may include any suitable hardware, software, components,modules, interfaces, or objects that facilitate the operations thereof.This may be inclusive of appropriate algorithms and communicationprotocols that allow for the effective exchange of data or information.For example, server farms 14 a and 14 b may be replaced with LANsconnecting desktop computers in a small office. In another example,server farms 14 a and 14 b may be replaced with a network of wirelesscommunication devices. In yet another example, server farms 14 a and 14b may be replaced with one or more supercomputers. Various otherconfigurations and devices are contemplated within the broad frameworkof the present disclosure.

According to embodiments of the present disclosure, system 10 mayprovide for a fabric extender (FEX)-like protocol, auto-discovery,message transport service (MTS)-like control messages, and definedmessages between service appliance 24 and switch 22. Configuration ofservice appliance 24 may be performed on switch 22 as for a line card.Data path forwarding may be offloaded to network line cards in switch22. Control path processing may be offloaded to a supervisor engine onswitch 22 as appropriate. In embodiments where service appliance 24 hasmultiple virtual services (e.g., virtual machines), each virtual servicemay be a separate virtual line card on switch 22.

Turning to FIG. 2, FIG. 2 is a simplified block diagram illustratingexample details of system 10 according to embodiments of the presentdisclosure. A supervisor engine 60 on switch 22 may communicate serviceappliance 24 via a line card including a fabric port 62 that connectspoint-to-point to a node on service appliance 24. Supervisor engine 60may include several modules such as an installer 64, an Ethernet portmanager (ethPM) 66, a port-channel manager (PCM) 68, a Quality ofService (QoS) element 70, a route policy manager (RPM) 72, aunified/unicast routing information base (URIB) 74, an access controllist manager (ACLmgr) 76, and a service policy manager (SPM) 78 forperforming various routing and/or management functions. ISCM 28 may beprovisioned in supervisor engine 60 to provide RISE relatedfunctionalities. ISCM 28 may manage one or more service modules,including in-chassis service modules and remote service modules.

In various embodiments, service appliance 24 may support stream controltransmission protocol (SCTP) with various addresses (e.g., 127addresses). In the absence of native SCTP support in supervisor engine60, tunneling over UDP may be enforced to send SCTP packets. A Netstackmodule 80 may be provisioned in supervisor engine 60 for implementingTCP/IP stack for received frames hitting the control-plane of supervisorengine 60. Supervisor engine 60 may be configured with an inband port82, which may be a virtual port that provides an interface formanagement traffic (such as auto-discovery) to a management processorsuch as a processor 86.

According to various embodiments, ISCM 28 may offer variousfunctionalities such as handling (i.e., accommodating, managing,processing, etc.) RISE messages (e.g., in MTS format), high availabilityactivities, timer events, packet switch stream (PSS), American StandardCode for Information Interchange (ASCII) generation, logging, eventhandling, health monitoring, debugging, etc. ISCM 28 may be a finitestate machine utility (FSMU) based application (e.g., which indicates anabstract machine that can be in one of a finite number of states). Invarious embodiments, ISCM 28 may have a well-defined MTS seamlessauthentication protocol (MTS SAP) assigned and it can open asocket-based MTS queue and bind to the well-defined SAP such that otherprocesses may communicate with it.

In various embodiments, ISCM 28 may also maintain an array of MTSoperation code (“opcode”), which can define how to process a receivedMTS message. The array may include per-opcode specific MTS flags,handler functions, etc. ISCM 28 may be configured to receive CLI drivenMTS messages, MTS notifications (such as event driven messagesindicating, for example, that a particular VLAN is up or down), and MTSrequest/responses. In various embodiments, ISCM 28 may be configured sothat MTS-based communication with other processes may be non-blockingand asynchronous. Thus, ISCM 28 may handle multiple events (which canarrive at any time) for the same resource such that the state of theresource is consistent (and not compromised). A similar opcode can beprovided even in non-MTS messages, which serves to indicate how to aswitch or a service can process the message.

Subsequent to ports (e.g., appliance ports and switch ports) beingconfigured in RISE mode, auto-discovery and bootstrap may be performedby ISCM 28 and ISCC 30 to establish an appropriate control channel.After the control channel is established, applications in serviceappliance 24 may send control messages (e.g., using the UDP socketinterface) to ISCC 30 through an application control plane 84.Application control plane 84 generally encompasses one or more softwarecomponents for performing workflow management, self-management, andother application control layer processes. ISCC 30 may forward thecontrol messages to ISCM 28 of switch 22 over communication channel 26.In example embodiments, ISCM 28 and ISCC 30 may communicate via UDPpackets; however, various other protocols and formats may beaccommodated by the teachings of the present disclosure. Supervisor 60may be provisioned with (or have access to) processor 86 and a memory 88for performing its various functions. ISCM 28 may use processor 86 andmemory 88 to perform RISE related functions in switch 22. Similarly,service appliance 24 may be provisioned with (or have access to) aprocessor 90 and a memory 92. ISCC 30 may use processor 90 and memory 92to perform RISE related functions in service appliance 24.

NAM

Network Appliance Monitoring or Network Appliance Module (NAM) refersto, interchangeably, a process of and a module for monitoring networkelements such as e.g. switches 22, and other devices that have largeamounts of data traffic flowing in, out, and within a data center. Suchmonitoring is conventionally performed e.g. by tapping the trafficor/and obtaining a copy of the traffic. One problem with suchconventional monitoring is that packet contents typically containlimited amount of information and/or information that is unreadable dueto e.g. encryption. In addition, there is no contextual information asto e.g. from which network element a packet may be originating or whichnetwork element a packet may be traversing. Contextual information iskey to correlating events in the network to support making ofintelligent decisions or fixing of network issues. Therefore, improvedsystems and methods for NAM are needed.

In the following, the term “NAM module” is used to describe anappliance, e.g. the service appliance 24 as described in FIGS. 1A-1B and2, configured to perform Network Appliance Monitoring on a networkelement, e.g. the switch 22 as described in FIGS. 1A-1B and 2 (e.g.Cisco Nexus 7000, 6000, or 5000 series switches).

Network Appliance Monitoring by Remotely Executing Commands

Embodiments of the present disclosure provide a NAM mechanism for a NAMmodule to mine information from a network element by opening up acommunication channel in a form of a remote execution channel betweenthe NAM module and the network element and using the communicationchannel for executing commands on the network element. In variousembodiments, the NAM module may be attached to the switch or/andresiding on the switch (i.e., an on-board appliance).

FIG. 3 illustrates a NAM mechanism 100 for mining information byremotely executing commands, according to an embodiment of the presentdisclosure. As shown in FIG. 3, the mechanism 100 involves a NAMconfiguration manager (also referred to as a “listener”) 102, a RemoteCommand Manager 104, and a Command Process 106. The NAM configurationmanager 102 is a functional element in a NAM module such as the serviceappliance 24 (which could be a part of the ISCC 30 configured to useprocessor 90 and memory 92 to perform RISE related functions in serviceappliance 24), while the Remote Command Manager 104 and the CommandProcess 106 are functional elements in a network element such as theswitch 22 (which could be parts of the ISCM 28 configured to useprocessor 86 and memory 88 to perform RISE related functions in switch22).

First, the NAM configuration manager 102 is configured to provide acommand to the switch 22 (e.g. RISE_CMD_EXEC message), in particular tothe Remote Command Manager 104 of the switch 22, over a communicationchannel 26, e.g. the RISE channel described above. Examples of providingsuch a command are shown in FIG. 3 as steps 108 and 110, where the NAMconfiguration manager 102 provides to the Remote Control Manager 104 ashow command and an execution command, respectively.

The command received at the Remote Command Manager 104 triggers theswitch 22 to determine whether execution of the received command, on theswitch 22, is allowed. To that end, in an embodiment, the Remote ControlManager 104 may be configured to filter Command Line Interface (CLI) todetermine whether the received command is one of the commands that areallowed to be executed on the switch 22 and, possibly, to determinewhether the particular service appliance 24 that provided the command isallowed to request execution of such a command.

In an embodiment, the NAM module may be configured to first send amessage to the monitored network element requesting the dictionary ofcommands that are allowed to be executed by this NAM module on theswitch. For example, the NAM module may send such a message once it isbooted, or as a part of a booting process. The network element wouldthen respond with a set commands that are acceptable (i.e. would beallowed for execution). The NAM module would receive this response,store the list of commands, only provide commands that are on the list,thus minimizing rejections of requests for execution.

In an embodiment, an opcode for the message requesting the dictionary ofcommands could be RISE_OPC_CMD_DICT. When the switch receives theRISE_CMD_EXEC message from the NAM module, it checks the commands in themessage against the dictionary it has. If a command is not present onthe dictionary, the switch will skip applying the command and send anerror message to the NAM module.

In an embodiment, the switch may be configured to send a message to theNAM module identifying new CLI added to the dictionary.

Once the Remote Control Manager 104 determined that the received commandmay be executed, it may spawn (initiate) command process, as shown withstep 112.

As shown with step 114, the Command Process 106 then runs (i.e.,executes) a show or an execution command on the network element,possibly on a particular VDC element of the network element. The resultof the command execution can be sent back to the originator/appliance,in this case to the NAM configuration manager 102, e.g. to a listeningTCP/UDP port that is running a listener thread. This is shown in FIG. 3with steps 116 and 118, where the command process 106 returns, to theNAM configuration manager 102, at least a part of the output of the showcommand (step 116) and returns success or error code for the result ofthe execution command (step 118). The information returned can be in anExtensible Markup Language (XML) format, Simple Network ManagementProtocol (SNMP), plain text, or any other format that a switch supports,e.g. as requested by the NAM module. The NAM configuration manager 102may then store the output provided by the command process 106 and,optionally, display the results to a user, e.g. via a graphical userinterface (GUI) provided on the NAM module. Such a GUI may also be usede.g. for enabling an administrator of the NAM module to specify outputformat for information returned from the network element.

In an embodiment, the mechanism described herein may gather/accessinformation based on Role-Based Authentication information, i.e. theRemote Command Manager 104 may be configured to determine whetherexecution of a command provided by the NAM configuration manager 102 onthe network element is allowed based on role-based authentication of theparticular service appliance 24 that provided the command.

In an embodiment, the Remote Configuration Manager 104 may provide amessage to the NAM module, authenticating the module, e.g.auth_key[RISE_AUTH_STR_LEN] field can be filled to send a predeterminedstring that authorizes a particular NAM module.

In an embodiment, the mechanism described herein may provideAuthenticated access/control based on a set of dictionary-based keys,such as e.g. verbs.

In an embodiment, the mechanism described herein may facilitate or retryof configuration at chassis, e.g. configuring SPAN sessions and/ordisabling or enabling SPAN sessions. Some examples of such configurationare described in greater detail in a following section.

Embodiments of the present disclosure provide a reliable mechanism for aNAM module to remotely execute commands on a network element. Themechanism uses a control protocol, e.g. RISE protocol described herein,between the switch and the NAM module. A variety of formats and data canbe used by the NAM module in order to retrieve data from the networkelement being monitored. In this manner, massive capital expenditures(CAPEX) and operational expenditures (OPEX) may be achieved by easilyintegrating a NAM module with a network element such as a switch or arouter. The mechanism allows faster and better performance as comparedto other techniques such as e.g. SNMP. Different types of format may besupported, based on the requirements of a monitoring device. Byproviding a dictionary of commands, access may be restricted based onthe type of monitoring device or application.

NAM Module Enabling Dynamic VDC Aware SPAN

Often, users of a NAM module may wish to monitor traffic in more thanone VDC elements on a switch 22. However a NAM module typically only hasone physical data link connected to one VDC. In order to SPAN traffic toa different VDC, the data link needs to be moved to that VDC. Thismanual process of moving ports can be tedious and error-prone.

Embodiments of the present disclosure enable monitoring network trafficon multiple VDCs of a switch using a single NAM module. To that end, ifa monitored network element supports contexts (i.e. VDC elements), a NAMmodule could be configured to seamlessly drive the move of the data portinterfaces (at the managed device) from one context to the other (step 1described in greater detail below). After the move of the data portsthat support SPAN destination traffic flow to the target VDC iscomplete, these SPAN destination ports may be configured to be able toreceive SPAN data traffic (step 2 described in greater detail below).The configuration of the SPAN destination ports may be automatic in thatit may be driven by a NAM module itself without the intervention of aswitch administrator (e.g. Nexus administrator), which qualifies theprocess to be called “Dynamic VDC aware SPAN.”

Such a scenario is illustrated in FIG. 4, depicting a system 200 where asingle NAM module 204 (shown as NAM appliance) is configured monitor anumber of VDC elements 206 on a Nexus 7000 switch. As shown in FIG. 4,the NAM module 204 may comprise or be communicatively connected to a NAMGraphical User Interface (GUI) client 202. Such a GUI client may beconfigured to receive user input e.g. regarding user's desire to monitortraffic on another VDC. In this manner, a user on the NAM module's sideis able to monitor traffic on an interface in any VDC. In FIG. 4, anarrow 208 illustrates bi-directional control traffic (e.g. a managementlink in the form of a RISE channel as described above), while arrows 210illustrate unidirectional auto-SPAN traffic.

While FIG. 4 depicts and the following illustrative descriptiondescribes a scenario with four VDCs and the network element as being aNexus 7000 (N7k) switch, teachings provided herein are applicable to anyother number of VDCs and any other kind of a network element withmultiple VDCs, which are all within the scope of the present disclosure.

First, a data port of the NAM module 204 is connected to a data port ofthe monitored network element such as e.g. a switch 22 (in FIG. 4—theN7K switch) and that data port of the switch is allocated to a first VDC(VDC-1). In step 1, in order to seamlessly drive the move of the dataport interfaces, e.g. for configuring dynamic VDC aware SPAN, the NAMmodule 204 is configured to provide to the switch a command triggeringthe switch to allocate the data port of the switch that is connected tothe data port of the NAM module to another VDC, e.g. VDC-2. To that end,the NAM module 204 may be configured to provide a command comprisingthree parameters: an indication of the NAM data port connected to thedata port of the monitored switch, an identification of VDC-2 to bemonitored (i.e., the target VDC where the SPAN has to be set up), and anidentification of a data port of the second VDC element to be monitored(i.e., the SPAN source port of the target VDC). In an embodiment, theseparameters may be provided via the GUI 202.

Such a command provided from the NAM module to the switch could bereferred to as an Auto SPAN message, received on the RISE channel. In anembodiment, the following message may be used for this step:RISE_CMD_EXEC, with possible sub opcodes including SHOW and EXECUTE, asdescribed above. Further discussions provided above regarding remoteexecution of commands on a switch provided above in context with the NAMconfiguration manager 102 and the Remote Control Manager 104 areapplicable here, and, therefore, in the interests of brevity, are notrepeated here.

In step 2, upon receiving the RISE_CMD_EXEC command from the NAM module,the switch will accordingly configure SPAN ports to be able to receiveSPAN data traffic (i.e. set up the SPAN session by executing thecommands sent in the RISE_CMD_EXEC request). To that end, the switchwill configure the data port of the second VDC element to be monitoredas a SPAN source port of VDC-2 and will move the destination SPAN portto target VDC by allocating the data port of the switch to which thedata port of the NAM module is physically connected to VDC-2 (inparticular, by configuring that data port of the switch as a SPANdestination port of VDC-2).

In an embodiment, the switch executing the move of the data portinterfaces may be viewed as the switch carrying out three steps: 1)allocate interface to the target VDC, 2) set the ‘switchport’ and‘monitor’ mode on the physical interface, and 3) initiate the SPANconfiguration for monitor session to set source and destination.

An example of the switch instating the SPAN configuration for amonitored session to set up source and destination is provided below:

  typedef struct rise_cmd_exec_req_ { uint32_t message_id; uint32_tmessage_code; uint32_t vdc_id; char auth_key[RISE_AUTH_STR_LEN];uint16_t port; uint16_t cmd_type; uint16_t cmd_len; uint8_t cmd[0]; }rise_cmd_exec_req_t;

Additional messages may be exchanged between the switch and the NAMmodule for initiation and completion of auto span service.

For example, the switch may provide to the NAM module a messageidentifying the VDC elements instantiated on the switch. An example ofsuch a message is VDC_INFO message as follows:

  typedef struct rise_nam_vdc_info_t_ { uint16_t vdc_id; charvdc_label[MAX_VDC_NAME_LEN]; } rise_nam_vdc_info_t;

The above message notifies the NAM module of the VDC ID and name ofactive VDCs available in the managed device.

Another example is a DATA_PORT_INFO message provided from the switch tothe NAM module in order to notify the NAM module about which NAM dataport is connected to which managed device interface. This informationmay then displayed on the NAM GUI interface, allowing a user of the NAMmodule to create SPAN sessions as desired. An example of aDATA_PORT_INFO message is provided below:

  typedef struct rise_data_port_info_ { uint16_t port_no; charphy_intf[RISE_MAX_INTF_NAME_LEN]; } rise_data_port_info_t;

Once the data port interfaces have been reconfigured, the NAM module mayalso execute commands on the second VDC (VDC-2), by providing respectivecommands on the management link and receiving data on the data link, asdescribed above.

Dynamic VDC Aware SPAN—Multiple Chassis

In an embodiment, dynamic VDC aware SPAN may be extended to multiplechassis (i.e. to multiple monitored network elements, e.g. multipleswitches). As the NAM module typically has a single management port,that port is used to directly attach to one monitored network element,e.g. a first switch such as the switch 22 (in FIG. 5—the N7K−1 switch,in FIG. 6—a switch 218). A second network element (e.g. another switch,in FIG. 5—the N7K−2 switch, in FIG. 6—a switch 220) is connected to thefirst. In an embodiment of multiple chassis without a virtualport-channel (“vPC”), i.e. a physical group of interfaces behaving asone logical interface, shown in FIG. 5, the connection may be via an L3link. Alternatively, the connection may be via a vPC, as shown in FIG.6. Thus, in a multiple chassis embodiment, a management port of a NAMmodule may be attached to a monitored network element either directly orindirectly whereas the data ports are directly attached. For the casewhen the management port is directly attached (e.g. between the NAMappliance and the N7K−1 switch or switch 218), there could be a physicalcable that connects the two ports. For the case when the management portis indirectly attached (e.g. between the NAM appliance and the N7K−2switch or switch 220), the connectivity could be achieved over an L2network (vPC peer link or some other L3 link).

FIG. 5 illustrates a NAM module (shown as “NAM appliance”), such as e.g.the NAM module 204, communicatively connected to a first chassis N7K−1and a second chassis N7K−2. Lines 212 illustrate NAM data ports, while aline 214 illustrates a NAM management interface. In addition, line 216illustrates a communication management link, e.g. an L3 link, betweenthe first and the second chassis. This link is used to indirectly attachthe second chassis to the NAM module. In other words, this connectionbehaves as the management link from the NAM module to the second switch.In this manner, a single management port on a NAM module may be used tosupport RISE services in multiple managed devices/switches. The dataport links on NAM module may be distributed between the two or moreswitches based on the user's need.

Support for the indirect mode RISE service is needed for the topology inwhich one NAM module is connected to multiple chassis. In such atopology, one connection will be direct and the others will be indirectmode. Through the direct mode, a switch may provide the IP to the NAMmodule and it gets auto configured. For the remaining indirect modeconnections, a switch may be configured to find the NAM module and makeTCP connections, without the need for L2 discovery and IP addressallocation (L3 discovery may still be needed to create the RISEservice).

FIG. 6 illustrates a NAM module communicatively connected to two networkelements 218 and 220 (e.g. N7K switches) for vPC 222, according to anembodiment of the present disclosure. In an embodiment, traffic comingfrom a switch 224 (Catalyst switch) may be hashed to one of the two (ormore) switches in the vPC 222, thus providing redundancy and highavailability because if one of the switches malfunctions, the otherswitch can still handle the traffic. In FIG. 6, lines 226 and 228illustrate NAM data ports, while a line 230 illustrates a NAM managementinterface.

Embodiments related to the Network Appliance Monitoring by remotelyexecuting commands and related to the NAM module enabling VDC aware SPANare applicable to the multiple chassis topologies illustrated in FIGS. 5and 6, possibly with modifications that would be apparent to a personskilled in the art based on the description provided herein. In theinterests of brevity, those descriptions are not repeated here.

Embodiments of the present disclosure provide a single NAM module withvisibility to all VDCs in a managed device. A user may utilize a NAM GUIto create SPAN sessions to monitor traffic in a VDC and the embodimentsdescribed herein allow to automatically move the ports to the requiredVDC and apply the SPAN configuration. In this manner, a single NAMmodule is able to monitor traffic in any VDC without changing thephysical wiring.

Further, embodiments of the present disclosure provide a reliablemechanism for configuring multiple SPAN sessions, e.g. for up to fourNAM data ports, using a NAM GUI. Embodiments of the present disclosurefurther allow using the NAM GUI for creating, editing, and deleting SPANsessions and selecting destination ports and source ports for the SPANsessions. The options of SPAN configuration available to N7K CommandLine Interface (CLI) users may be made available via NAM GUI using RISE.

VARIATIONS AND IMPLEMENTATIONS

Note that in this Specification, references to various features (e.g.,elements, structures, modules, components, steps, operations,characteristics, etc.) included in “one embodiment”, “exampleembodiment”, “an embodiment”, “another embodiment”, “some embodiments”,“various embodiments”, “other embodiments”, “alternative embodiment”,and the like are intended to mean that any such features are included inone or more embodiments of the present disclosure, but may or may notnecessarily be combined in the same embodiments. Furthermore, the words“optimize,” “optimization,” and related terms are terms of art thatrefer to improvements in speed and/or efficiency of a specified outcomeand do not purport to indicate that a process for achieving thespecified outcome has achieved, or is capable of achieving, an “optimal”or perfectly speedy/perfectly efficient state.

In example implementations, at least some portions of the activitiesoutlined herein may be implemented in software in, for example,provisioned in service appliance 24 and/or switch 22 (e.g., throughvarious modules, algorithms, processes, etc.). In some embodiments, oneor more of these features may be implemented in hardware, providedexternal to these elements, or consolidated in any appropriate manner toachieve the intended functionality. Service appliance 24 and/or switch22 may include software (or reciprocating software) that can coordinatein order to achieve the operations as outlined herein. In still otherembodiments, these elements may include any suitable algorithms,hardware, software, components, modules, interfaces, or objects thatfacilitate the operations thereof.

Furthermore, switch 22 and service appliance 24 described and shownherein (and/or their associated structures) may also include suitableinterfaces for receiving, transmitting, and/or otherwise communicatingdata or information in a network environment. Additionally, some of theprocessors and memories associated with the various network elements maybe removed, or otherwise consolidated such that a single processor and asingle memory location are responsible for certain activities. In ageneral sense, the arrangements depicted in the FIGURES may be morelogical in their representations, whereas a physical architecture mayinclude various permutations, combinations, and/or hybrids of theseelements. It is imperative to note that countless possible designconfigurations can be used to achieve the operational objectivesoutlined here. Accordingly, the associated infrastructure has a myriadof substitute arrangements, design choices, device possibilities,hardware configurations, software implementations, equipment options,etc.

In some of example embodiments, one or more memories (e.g., memory 92,memory 88) can store data used for the operations described herein. Thisincludes the memory being able to store instructions (e.g., as part oflogic, software, code, etc.) that are executed to carry out theactivities described in this Specification. A processor can execute anytype of instructions associated with the data to achieve the operationsdetailed herein in this Specification. In one example, processors 86 andprocessor 90 could transform an element or an article (e.g., data) fromone state or thing to another state or thing. In another example, theactivities outlined herein may be implemented with fixed logic orprogrammable logic (e.g., software/computer instructions executed by aprocessor) and the elements identified herein could be some type of aprogrammable processor, programmable digital logic (e.g., a fieldprogrammable gate array (FPGA), an erasable programmable read onlymemory (EPROM), an electrically erasable programmable read only memory(EEPROM)), an ASIC that includes digital logic, software, code,electronic instructions, flash memory, optical disks, CD-ROMs, DVD ROMs,magnetic or optical cards, other types of machine-readable mediumssuitable for storing electronic instructions, or any suitablecombination thereof.

In operation, components in system 10 can include one or more memoryelements (e.g., memory 88, memory 92) for storing information to be usedin achieving operations as outlined herein. These devices may furtherkeep information in any suitable type of non-transitory storage medium(e.g., random access memory (RAM), read only memory (ROM), fieldprogrammable gate array (FPGA), erasable programmable read only memory(EPROM), electrically erasable programmable ROM (EEPROM), etc.),software, hardware, or in any other suitable component, device, element,or object where appropriate and based on particular needs. Theinformation being tracked, sent, received, or stored in system 10 couldbe provided in any database, register, table, cache, queue, controllist, or storage structure, based on particular needs andimplementations, all of which could be referenced in any suitabletimeframe. Any of the memory items discussed herein should be construedas being encompassed within the broad term ‘memory.’ Similarly, any ofthe potential processing elements, modules, and machines described inthis Specification should be construed as being encompassed within thebroad term ‘processor.’

It is also important to note that the operations and steps describedwith reference to the preceding FIGURES illustrate only some of thepossible scenarios that may be executed by, or within, the system. Someof these operations may be deleted or removed where appropriate, orthese steps may be modified or changed considerably without departingfrom the scope of the discussed concepts. In addition, the timing ofthese operations may be altered considerably and still achieve theresults taught in this disclosure. The preceding operational flows havebeen offered for purposes of example and discussion. Substantialflexibility is provided by the system in that any suitable arrangements,chronologies, configurations, and timing mechanisms may be providedwithout departing from the teachings of the discussed concepts.

Although the present disclosure has been described in detail withreference to particular arrangements and configurations, these exampleconfigurations and arrangements may be changed significantly withoutdeparting from the scope of the present disclosure. For example,although the present disclosure has been described with reference toparticular communication exchanges involving certain network access,formatting, and protocols, system 10 may be applicable to otherexchanges, formats, or routing protocols. Moreover, although system 10has been illustrated with reference to particular elements andoperations that facilitate the communication process, these elements,and operations may be replaced by any suitable architecture or processthat achieves the intended functionality of system 10.

Numerous other changes, substitutions, variations, alterations, andmodifications may be ascertained to one skilled in the art and it isintended that the present disclosure encompass all such changes,substitutions, variations, alterations, and modifications as fallingwithin the scope of the appended claims (if any) or examples. In orderto assist the United States Patent and Trademark Office (USPTO) and,additionally, any readers of any patent issued on this application ininterpreting the claims (if any) or examples appended hereto, Applicantwishes to note that the Applicant: (a) does not intend any of theappended claims or examples (if any) to invoke paragraph six (6) of 35U.S.C. section 112 as it exists on the date of the filing hereof unlessthe words “means for” or “step for” are specifically used in theparticular claims (if any) or examples; and (b) does not intend, by anystatement in the specification, to limit this disclosure in any way thatis not otherwise reflected in the appended claims (if any) or examples.

Although the claims are presented in single dependency format in thestyle used before the USPTO, it should be understood that any claim candepend on and be combined with any preceding claim of the same typeunless that is clearly technically infeasible.

What is claimed is:
 1. A method comprising: providing, from a networkappliance monitoring (NAM) module residing in hardware, the NAM modulecomprising a NAM data port physically connected to a network elementdata port of a network element through a data communication link, thenetwork element data port being allocated to a first Virtual DesignContext (VDC) element of a plurality of VDC elements instantiated on thenetwork element, to the network element, over a management communicationlink between the NAM module and the network element, a first commandfrom the NAM module triggering the network element to allocate thenetwork element data port to a second VDC element of the plurality ofVDC elements, such that the network element data port is reassigned fromthe first VDC element to the second VDC element; following allocation ofthe network element data port to the second VDC element, monitoringtraffic flow on the second VDC element by receiving, at the NAM module,from the network element, over the data communication link between theNAM data port and the network element data port, the traffic flow fromthe second VDC element; providing a second command from the NAM moduleto the second VDC element over the management communication link betweenthe NAM module and the network element, the second command triggeringthe network element to determine whether execution of the second commandon the second VDC element is allowed and, upon positive determination,execute the second command on the second VDC element; and receiving, atthe NAM module, from the network element, over the data communicationlink between the NAM data port and the network element data port atleast part of an output resulting from the execution of the secondcommand.
 2. The method according to claim 1, wherein the first commandincludes an indication of the NAM data port that is physically connectedto the network element data port, an identification of the second VDCelement, and an identification of a data port of the second VDC elementto be monitored.
 3. The method according to claim 2, wherein the firstcommand triggers the network element to configure the data port of thesecond VDC element to be monitored as a SPAN source port of the secondVDC element.
 4. The method according to claim 1, wherein triggering thenetwork element to allocate the network element data port to the secondVDC element comprises triggering the network element to configure thenetwork element data port as a SPAN destination port of the second VDCelement.
 5. The method according to claim 1, further comprising the NAMmodule performing network appliance monitoring based on the receivedtraffic flow from the second VDC element.
 6. A system comprising: atleast one memory configured to store computer executable instructions,and at least one processor coupled to the at least one memory andconfigured, when executing the instructions, to: provide, from a networkappliance monitoring (NAM) module residing in hardware, the NAM modulecomprising a NAM data port physically connected to a network elementdata port of a network element through a data communication link, thenetwork element data port being allocated to a first Virtual DesignContext (VDC) element of a plurality of VDC elements instantiated on thenetwork element, to the network element, over a management communicationlink between the NAM module and the network element, a first commandfrom the NAM module triggering the network element to allocate thenetwork element data port to a second VDC element of the plurality ofVDC elements, such that the network element data port is reassigned fromthe first VDC element to the second VDC element; following allocation ofthe network element data port to the second VDC element, monitor trafficflow on the second VDC element by receiving, at the NAM module, from thenetwork element, over the data communication link between the NAM dataport and the network element data port, the traffic flow from the secondVDC element; wherein the at least one processor is further configured tocontrol execution of a second command on the second VDC element by:providing the second command from the NAM module to the second VDCelement over the management communication link between the NAM moduleand the network element, the second command triggering the networkelement to determine whether execution of the second command on thesecond VDC element is allowed and, upon positive determination, executethe second command on the second VDC element; and receiving, at the NAMmodule, from the network element, over the data communication linkbetween the NAM data port and the network element data port at leastpart of an output resulting from the execution of the second command. 7.The system according to claim 6, wherein the first command includes anindication of the NAM data port that is physically connected to thenetwork element data port, an identification of the second VDC element,and an identification of a data port of the second VDC element to bemonitored.
 8. The system according to claim 7, wherein the first commandtriggers the network element to configure the data port of the secondVDC element to be monitored as a SPAN source port of the second VDCelement.
 9. The system according to claim 7, wherein the at least oneprocessor is further configured to provide a user interface enabling auser to at least provide user input indicating one or more of the NAMdata port, the second VDC element, and the data port of the second VDCelement to be monitored.
 10. The system according to claim 6, whereintriggering the network element to allocate the network element data portto the second VDC element comprises triggering the network element toconfigure the network element data port as a SPAN destination port ofthe second VDC element.
 11. The system according to claim 6, wherein themanagement communication link comprises a Remote Integrated ServiceEngine (“RISE”) channel.
 12. The system according to claim 6, whereinthe network element includes an intelligent service card manager module(“ISCM”) that forms part of a Remote Integrated Service Engine (“RISE”)element with a corresponding intelligent service card client module(“ISCC”) installed on the NAM module.
 13. The system according to claim6, wherein the at least one processor is further configured to receive,at the NAM module, from the network element, information identifying theplurality of VDC elements instantiated on the network element.
 14. Thesystem according to claim 6, wherein the at least one processor isfurther configured to receive, at the NAM module, from the networkelement, data port connection information indicating how each data portof a plurality of data ports of the NAM module is connected to one dataport of a plurality of data ports of the network element.
 15. The systemaccording to claim 6, wherein the NAM module performs network appliancemonitoring based on the received traffic flow from the second VDCelement.
 16. One or more non-transitory computer readable storage mediaencoded with software comprising computer executable instructions which,when the software is executed, are operable to: provide, from a networkappliance monitoring (NAM) module residing in hardware, the NAM modulecomprising a NAM data port physically connected to a network elementdata port of a network element through a data communication link, thenetwork element data port being allocated to a first Virtual DesignContext (VDC) element of a plurality of VDC elements instantiated on thenetwork element, to the network element, over a management communicationlink between the NAM module and the network element, a first commandfrom the NAM module triggering the network element to allocate thenetwork element data port to a second VDC element of the plurality ofVDC elements, such that the network element data port is reassigned fromthe first VDC element to the second VDC element; following allocation ofthe network element data port to the second VDC element, monitor trafficflow on the second VDC element by receiving, at the NAM module, from thenetwork element, over the data communication link between the NAM dataport and the network element data port, the traffic flow from the secondVDC element; provide a second command from the NAM module to the secondVDC element over the management communication link between the NAMmodule and the network element, the second command triggering thenetwork element to determine whether execution of the second command onthe second VDC element is allowed and, upon positive determination,execute the second command on the second VDC element; and receive, atthe NAM module, from the network element, over the data communicationlink between the NAM data port and the network element data port atleast part of an output resulting from the execution of the secondcommand.
 17. The one or more non-transitory computer readable storagemedia according to claim 16, wherein the first command includes anindication of the NAM data port that is physically connected to thenetwork element data port, an identification of the second VDC element,and an identification of a data port of the second VDC element to bemonitored.
 18. The one or more non-transitory computer readable storagemedia according to claim 17, further operable to provide a userinterface enabling a user to at least provide user input indicating oneor more of the NAM data port, the second VDC element, and the data portof the second VDC element to be monitored.
 19. The one or morenon-transitory computer readable storage media according to claim 16,wherein triggering the network element to allocate the network elementdata port to the second VDC element comprises triggering the networkelement to configure the network element data port as a SPAN destinationport of the second VDC element.
 20. The one or more non-transitorycomputer readable storage media according to claim 16, wherein thenetwork element includes an intelligent service card manager module(“ISCM”) that forms part of a Remote Integrated Service Engine (“RISE”)element with a corresponding intelligent service card client module(“ISCC”) installed on the NAM module.
 21. The method according to claim1, further comprising: prior to providing the first command,establishing the management communication link between the NAM moduleand the network element, wherein the management communication link is acommunication channel of a Remote Integrated Service Engine (RISE)protocol.
 22. The method according to claim 1, wherein triggering thenetwork element to allocate the network element data port to the secondVDC element comprises: (i) configuring the data port of the second VDCelement to be monitored as a SPAN source port of the second VDC element,and (ii) configuring the network element data port as a SPAN destinationport of the second VDC element.